Problem error checking -match and IF statement - powershell

Question

The below script will import an exported CSV from our MIS system so that we can upload to google classroom. In tern, this will allow bulk creation of classes with our custom classnames based on word matching within the regex.csv.
As you can see from the exporteddata.csv, 10552 is blank.
Is it possible for this to be omitted from the final export and added into its own errors.csv file?
Any help would be great!
Script.ps1
$data = Import-Csv "$PSScriptRoot\data.csv" -Delimiter ','
$patterns = Import-Csv "$PSScriptRoot\Regex\regex.csv" -Delimiter ','
$interimexportedData = "$PSScriptRoot\classesinterim.csv"
$exportclasses = "$PSScriptRoot\exporteddata.csv"
## Imports the initial SIMS export of classes and created a 'prefered' name for the class, then exports to a CSV.
$data | Select-Object *,#{Name='preference'; Expression={
foreach ($p in $patterns) {
if ($_.title -match $p.'regex_key') {
$p.preference + " " + "-" + " " + $_.title
return
}
}
}
} | Select-Object -property sourcedID, preference | Export-Csv $interimexportedData -NoTypeInformation
## The below re-imports the csv file and renames the header
Import-Csv $interimexportedData |
Select-Object -property sourcedID, #{ expression={$_.preference}; label='title' } |
Export-Csv -NoTypeInformation $exportclasses
## Delete the classesinterim.csv from the folder
Remove-Item $interimexportedData
data.csv
"sourcedId","title"
9443,"10A/BS1"
9444,"10A/FR1"
10598,"10A/Ft"
9445,"10A/GG1"
9446,"10A/HI1"
9447,"10A/ME1"
9451,"10A/ME2"
9448,"10A/RM1"
9449,"10A/SCTrX"
9452,"10A/SCTrY"
10552,"10A/SOS"
9450,"10A/SP1"
exporteddata.csv
"sourcedId","title"
"9443","Business Studies - 10A/BS1"
"9444","French - 10A/FR1"
"10598","Form Time - 10A/Ft"
"9445","Geography - 10A/GG1"
"9446","History - 10A/HI1"
"9447","Media Studies - 10A/ME1"
"9451","Media Studies - 10A/ME2"
"9448","Resistant Materials - 10A/RM1"
"9449","Science - 10A/SCTrX"
"9452","Science - 10A/SCTrY"
"10552",""
regex.csv
"regex_key","preference"
BS,"Business Studies"
FR, "French"
Ar,"Art"
Bt,"Eng & Maths Booster"
Bs,"Business"
Cn,"Construction"
Co,"Computing"

Answer 1

Use Where-Object to filter out objects with a blank value:
$data | Select-Object *,#{Name='preference'; Expression={
foreach ($p in $patterns) {
if ($_.title -match $p.'regex_key') {
$p.preference + " " + "-" + " " + $_.title
return
}
}
} |Where-Object preference -ne ''